ENC424J600-I/ML Microchip Technology, ENC424J600-I/ML Datasheet - Page 133

• Manufacturer Part Number: ENC424J600-I/ML
• Description: IC ETHERNET CTRLR W/SPI 44-QFN
• Manufacturer: Microchip Technology

Specifications of ENC424J600-I/ML

• Package / Case: 44-QFN
• Controller Type: Ethernet Controller
• Interface: SPI
• Voltage - Supply: 3 V ~ 3.6 V
• Current - Supply: 96mA
• Operating Temperature: -40°C ~ 85°C
• Mounting Type: Surface Mount
• Input Voltage Range (max): 5.5 V
• Maximum Operating Temperature: + 85 C
• Minimum Operating Temperature: - 40 C
• Mounting Style: SMD/SMT
• Operating Supply Voltage: 3 V to 3.6 V
• Supply Current (max): 117 mA
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant
• For Use With: AC164132 - BOARD DAUGHTER PICTAIL ETHERNET
• Lead Free Status / Rohs Status: Lead free / RoHS Compliant

To encrypt a block using ECB mode:
1.
2.
3.
4.
5.
6.
7.
To decrypt a block using ECB mode:
1.
2.
3.
4.
FIGURE 15-2:
 2010 Microchip Technology Inc.
Load the encryption key as described in
Section 15.3.1 “Key Support” .
Set AESOP<1:0> (ECON1<10:9>) to ‘ 00 ’.
Copy the plaintext message to TEXTA at 7C20h.
Set AESST (ECON1<11>) to initiate the
encryption.
Wait for the hardware to clear AESST.
Read the ciphertext message from TEXTA at
7C20h.
Repeat steps 3 through 6 for subsequent blocks.
Initialize the decryption key as described in
Section 15.3.1 “Key Support” .
Set AESOP<1:0> to ‘ 10 ’.
Copy the ciphertext message to TEXTA at
7C20h.
Set AESST to initiate the decryption.
IV
Plaintext
ENCRYPTER
DATA
Ciphertext
0
ENCRYPTION
Key
KEY
CBC ENCRYPTION AND DECRYPTION
0
Plaintext
ENCRYPTER
DATA
Ciphertext
0
Key
KEY
1
ENC424J600/624J600
5.
6.
7.
The context for ECB mode includes only the encryption
key. No additional context data needs to be saved.
15.3.3.2
The Cipher Block Chaining mode uses feedback from
the encryption output to further obscure the ciphertext
data. During encryption, the first block uses an Initial-
ization Vector (IV) which is XORed with the plaintext
data. The output of this XOR function is then encrypted
using the AES key and this ciphertext becomes the IV
for the next block. Under CBC mode, each subsequent
block depends on the previous block. Therefore,
identical subsequent plaintext blocks use a different IV,
and therefore, yield different ciphertext blocks.
Figure 15-2 shows the use of CBC mode for encryption
and decryption.
IV
Wait for the hardware to clear AESST.
Read the plaintext message from TEXTA at
7C20h.
Repeat steps 3 through 6 for subsequent blocks.
Key
KEY
DECRYPTER
Plaintext
Cipher Block Chaining Mode (CBC)
Ciphertext
DATA
DECRYPTION
0
0
Key
KEY
DECRYPTER
DS39935C-page 131
Plaintext
Ciphertext
DATA
1
1